Usually the measuring unit of those measuring instruments comprise a movable part and a fixed part, wherein the movable part can be moved by the operator for contacting physically a distinct point of the object to be gauged. The fixed part is either brought into contact with another distinct point of the object before the movable part is brought into contact or the fixed part is hold in a position relative to the object to be gauged, which position is stabilized as soon as the movable part is in contact with the object (e.g. inside micrometer screws, like presented in FIG. 4).
Nowadays those handheld measurement instruments are mostly digital instruments provided with various functionalities, e.g. unit, resolution, data collection, data collection and statistic analysis, go/no-go tolerances and further more. Usually the functionality and the required function of the selected functionality can be selected by input buttons; e.g. one button is for selecting the functionality “unit” another one is for selecting the functionality “resolution”, a third one for “collecting data”, a fourth one for go/no-go tolerances. Further functionalities may be accessible by pushing not one button, but synchronously two buttons. To select the various functions included in a functionality the operator has, e.g. to push the according button repeatedly for jumping from one function to the next, or the operator has to push the same or another button for differing long times in order to select one of the functions under the according functionality. Other combinations of pressing one or more buttons are well known and also usable. Functions and functionalities commonly provided with those handheld measuring instruments are: SI-unit/imperial unit under the functionality “unit”; resolution degree, e.g. 0.1 mm, 0.05 mm, 0.001 mm, 0.005 mm or 0.01 in, 0.001 in, 0.0001 in, respectively under the functionality “resolution”; the number of data, which should be collected, under the functionality “collecting data”; various methods to analyse collected data, e.g. various types to calculate an average under the functionality “analysing data”; yes/no and value of a threshold under the functionality “go/no-go tolerance”; the single function of self-calibration under the functionality “start calibration”; and further functionalities dealing with the way the data are presented or measured and collected.
US 2008/0177503 A1 discloses a caliper comprising an electronic package with several buttons, which serve as input means that are used to control various operations of the caliper, such as turning the caliper on and off, selecting display configurations, resetting of a measurement and as well selecting the setting of information presentation such as first and/or second format, etc. The electronic package may further comprise a display controller with a memory and a circuit unit. The circuit unit controls presentation of information on a display by performing operations which may be, as well as the circuit unit itself, implemented as a computer programme product, that may be embodied in an information carrier like a CD-ROM or stored in form of software in the memory of the display controller. For performing the operations, the circuit unit uses preset presentation settings that control the display and format of measurement information, e.g. measurement units, decimal or fractional representation, etc. These presentation settings may be gathered from inputs, configuration switches or from settings stored in a memory, e.g. the memory of the display controller. Thus, the presentation settings, which e.g. determine the format of a measurement to be a decimal value, are preoperationally configured and read as a first step of the operations.
US 2003/0047009 A1 discloses a complex caliper comprising a force arm, a force gauge and a processor such that the force applied to the force arm can be detected and displayed. A variety of input means like control buttons allow a user to control the caliper. For example one control button allows the caliper to be turned on or off. Other control buttons are utilized to alter the mode of operation or display presentation respectively. Those operations and display presentation can be the format of a measurement result, alerts in dependence of a measurement such as an applied force, temporary disablement of functions, execution of algorithms for evaluation or alteration of measurement results, histories of measurement results, etc. Thus, the electronic circuit unit is controlled in its functionalities by using the input means. In a specific embodiment, the caliper may comprise an interface for communication with a computer for exchange of measurement data, to program various components and/or to provide a power supply or a display.
US 2002/01235859 A1 discloses a caliper with a digital display and a plurality of buttons for controlling various functions, as on/of, scale factor, conversion, re-zero and the like. The caliper is connectable to a computer or palm pilot by hardwire connection, radio frequency or infrared transmitter for data collection or other, not further specified purposes.
A disadvantage of all the above described calipers is that a variety of input buttons is needed to allow the user a selection of or between preset operations and/or functionalities and/or functions of a distinct functionality. This requires a corresponding number of breakthroughs in the housing of the caliper, which breakthroughs open the housing and the electronic equipment within the housing for humidity and dust.
As it can be seen, the increasing amount of functionalities requires an increasing number of buttons and by that usually an increasing number of breakthroughs in the casing of such a handheld measuring instrument. But using the measurement instrument in a rough and dirty environment like a construction side, a workshop or a plant, as it is usually done, each breakthrough means danger for the electronic equipment within the casing and for the precision of the measurement.